1. Field of the Invention
The present invention relates to a substrate processing apparatus, a method for using the same, and a computer readable medium containing program instructions for execution on a processor, and particularly to a vacuum processing technique utilized in semiconductor processing system. The term “semiconductor process” used herein includes various kinds of processes which are performed to manufacture a semiconductor device or a structure having wiring layers, electrodes, and the like to be connected to a semiconductor device, on a target substrate, such as a semiconductor wafer or a glass substrate used for an LCD (Liquid Crystal Display) or FPD (Flat Panel Display), by forming semiconductor layers, insulating layers, and conductive layers in predetermined patterns on the target substrate.
2. Description of the Related Art
An apparatus for processing a substrate, such as a semiconductor wafer, by plasma, such as a plasma etching apparatus, includes a vacuum process chamber and a susceptor (worktable) disposed therein for placing the substrate thereon. Since the substrate is heated due to plasma during processing, a temperature adjusting mechanism is built in the susceptor for cooling the substrate. The thermal conductivity between the susceptor and substrate depends on the substance present between them. When the interior of the process chamber is set in a vacuum state, the portion between the susceptor and substrate also becomes vacuum, and thus the thermal conductivity between them is extremely decreased (the thermal connection is cut off). Accordingly, in order to ensure the thermal conductivity, the susceptor is provided with a heat transfer gas supply mechanism configured to supply a heat transfer gas, such as helium (He) gas between the susceptor and substrate (for example, Jpn. Pat. Appln. KOKAI Publication No. 2002-252271 (Patent Document 1)).
The heat transfer gas is supplied at a predetermined flow rate and pressure from a gas supply section disposed below the susceptor. The heat transfer gas line (heat transfer gas supply passage) is provided with an MFC (Mass Flow Controller) and a PCV (Pressure Control Valve) configured to control the supply flow rate and pressure of the heat transfer gas. The MFC and PCV adjust the flow rate and pressure of the heat transfer gas in accordance with preset values prescribed in a plasma process menu (which will be referred to as a recipe).
When the substrate is removed from the susceptor, the heat transfer gas supply mechanism stops supply of the heat transfer gas, and thus the pressure inside the heat transfer gasoline is decreased. Accordingly, when a new substrate is placed on the susceptor and subjected to a plasma process, the pressure inside the heat transfer gas line needs to be increased to a predetermined pressure prescribed in a recipe.
In recent years, in order to improve the throughput, it is required to shorten the time period necessary for each of the steps of a plasma process. As regards the pressure increase of the heat transfer gas line, a so-called acceleration sequence is applied after a substrate is placed on the susceptor and before a plasma process (main process) is performed. Hereinafter, the acceleration sequence means an operation of supplying the heat transfer gas into the line thereof at a flow rate higher than the predetermined flow rate prescribed in the recipe. This operation shortens the time period necessary for increasing the pressure inside the line of the heat transfer gas supply mechanism.